Pattern and pattern making



Dec. 9, 1952 K. T. RINDERLE PATTERN AND PATTERN MAKING 2 SHEETS-SHEET 1Filed July 1, 1949 R. mm M me n e, VM 0 mm [wr r E ve r m n 4 Q. f6 57.,.

J l -A f6 Dec. 9, 1952 K. T. RINDERLE 2,620,529

y l, 1949 2 SHEETS-SHEET 2 IU Il INVENTOR.

KAR/ 7'. E/NDEELE.

Patented Dec. 9, 1952 UNITED STATES PATENT OFFICE Brown IndustriesIncorporated,

Sandusky,

Ohio, a corporation of Ohio Application July 1, 1949, Serial No. 102,610

9 Claims.

This invention relates to patterns and pattern making and moreparticularly to a novel method of forming fillets in the angles of suchpatterns and the provision of a smooth and wear-resistant surfacethereon.

Dead sharp inside corners are not permissible on any portion of apattern, whether constructed of metal, wood, or other material, wheresuch pattern is to be employed in the shaping of a sand mold. The usualmolding sand is, of course, granular in form and obviously cannot berammed completely into such corners. There will always be intersticesbetween the grains of sands which leave weak and unsupported corners inthe finished mold easily damaged in handling and subject to erosion andpenetration by the molten iron or other metal during pouring. Byrounding such inside corners of the pattern, however, it becomespossible to fill the same completely With properly packed sand so thatthe resultant edge or corner of the finished mold is reinforced andself-supporting. Additionally, there are various metallurgical reasonsfor avoiding a sharp sand :fe-entrant angle in a mold. These factors areWell understood in the art, and it is consequently a universal practiceto provide fillets in such pattern angles and also in the angle Wherethe pat- 'tern joins the pattern plate. Such fillets are ordinarilyformed to provide a slightly concave contour between the planes of theangle, the radius of the fillet required varying with the size of thegrains of the molding sand or other medium, a relatively small radiusbeing satisfactory when fine sand is to be employed and a larger radiusbeing necessary when a coarser grade of sand is used. Such fillets areregularly provided on wood or plaster master patterns and, where metalpatterns are cast integrally on a plate, a llet is provided at the jointby the pattern founder. On the other hand, when metal patterns aremounted on a separate metal plate, the mating surfaces require to bemachined, resulting in a dead sharp corner at the joint. The foundrymentherefore add a fillet at such joint using such materials as beeswaxmixed with aluminum powder, sealing wax, lacquer, various liquid sol-When wooden patterns are made, the necessary fillets have been providedin a variety of ways: by carving the same from the solid block of woodof which the pattern is formed; glueing in preformed wooden fillets;melting in wax and then forming the fillet by application of a hot metalrod; glueing in a preformed fillet consisting of an outer cloth coveringand an inner Wax filler; rubbing in a shaped wax fillet; glueing in ashaped leather or plastic fillet; forming a iillet of plastic wood orcrack filler; building up a llet with paint, shellac, lacquer, metalspray, glue, and liquid solder; forming the fillet of "caulkingcompounds; putty, or molding clay. None of the foregoing expedients hasproven satisfactory in practice although each method is currentlyemployed in one foundry or another. Such fillets rapidly deteriorate inuse and before long it is found that the molder in the foundry repairsthe same with such materials as clay dug from the floor or taken from acupola mud box. Inferior castings and scrap are the ultimate result.

The reasons for failure of these various expedients include expansionand contraction of the pattern components in use and storage which tearVthe applied fillets loose and crack the carved ones. Moisture may causethe edges of such applied fillets to curl back, while wax fillets tendto harden in cold weather and drop off or get soft and sticky in warmweather. causing sand to adhere thereto. Fillets of paint, lacquen'crackfiller, etc.. also fail due to expansion and contraction of the patternparts, jolting ofthe mold on the molding machine and the vibration orrapping usually employed to facilitate the draw.

It is therefore a primary object of this invention to provide a novelfillet which will have none of the lforegoing disadvantages but whichcan normally be expected to last for the life of the pattern.

Another object is to provide a method of forming such fillet which isequally applicable to both wooden and metal patterns.

Where a large number of identical castings are to be produced, it is theusual practice to employ metal patterns since the same naturally outlastwooden patterns and are more accurate in their dimensions and smootherof surface, On the other hand, Where the number of castings to be madeis insufiicient to justifyr the higher cost of such metal patterns andit is not necessary to hold to such precise dimensions, wooden patternsare customarily employed. It has been appreciated by workers in theindustry that a wooden pattern surfaced with applied metal or otherequivalent smooth and wear-resisting material Would be highly desirableas providing the advantages of the more expensive metal patterns at amuch reduced cost. Attempts have accordingly been made to spray variousmolten metal alloys on the usual wooden patterns but such attempts haveachieved but indifferent results. In the r'st place, the applied thinfilm of metal has failed to adhere satisfactorily to the underlyingpattern, particular difficulty arising at the llets. In the secondplace, such fillets still tend to break down in use despite the thinmetal coating applied thereover. It is therefore a further object ofmy'invention to provide a metal surfaced wooden patternlwhich will haveall of the advantages of the usual metal patterns and in Which theapplied metalcoating will Vbe permanently bonded to the underlyingpattern.

Still another object is to provide such metalcoated pattern having lletswhich will not loosen or otherwise deteriorate in use.

Other objectsv of :the invention `will appear .as the `descriptionproceeds.

To the accomplishment .of the foregoing rand related ends, saidinvention then comprises the features hereinafter fully described andparticularly pointed out in the claims, the following description andvthe annexed drawing setting forth in detail certain .illustrativeembodiments `of the invention, these being indicative, however, of but afewof the various Ways in which the principle of the invention may-beemployed.

In said annexed drawing:

Fig. 1 is a top plan view of a 4pattern plate formed in accordance withmyV invention for mounting of an appropriate pattern thereon;

Fig. 2 is a side elevational lview of such Ipattern plate;

Fig. 3 is a top plan View of such pattern plate showing a patternmounted thereon together with the means which I employ to form anappropriate fillet at the juncture of such pattern and pattern plate; v

Fig. 4 Vis a side elevational View of the assembly of Fig. 3;

Fig. 5 is an end elevational View of the assembly of Fig. 3

Fig. 6 is a fragmentary sectional view taken through such assembly alongthe line 6-.6 on Fig. 3; i

Fig. '7 is a similar fragmentarysectional view taken on the line 'I-"Ion Fig. 3;

Fig. 8 is a vertical sectional view taken on the line 8-8 on Fig. 3;

Fig. 9 is a top plan view of the pattern plate and pattern mountedthereon after formation of such fillet; and

Fig. 10 is a fragmentary vertical sectional view taken along the lineIll-I on Fig. 9, also showing the metal surface coating applied to suchpattern and pattern plate.

Referring noW more particularly to said drawing, I illustrate theformation of a 'fillet in the joint between the pattern and patternplate, although it will be appreciated that fillets may similarly beapplied in other pattern angles. The pattern I is placed upon thepattern plate 2 in the position it is to occupy thereon and aline istraced thereabout on such pattern plate. A groove 3 is then routed outin the upper surface of the pattern plate with` such .line constitutingthe approximate center line of the groove. The edges of the groove willpreferably be undercut much like a keyway.

The pattern is then secured to the pattern 4 plate by means of dowels 4inserted in holes 5 in the pattern and corresponding holes 6 in thepattern plate. An adhesive may also be applied to the mating surfaces ifdesired.

Referring now more particularly to Figs. 3-8 inclusive, I next place alength of ordinary leather belting 'I having a circular cross-sectionclosely around the pattern in the vangle between the latter and thepatternplate, the radius of such belting being the same as that desiredin the fillet to be produced. As shown in Fig. 8, the belting closesthat portion of groove 3 left exposed by pattern I. Such belting issecured in place by coveringxthesame with an oil base modeling cla-y A8which has been worked sufficiently soft that -it may be applied with asingle stroke of the thumb. Such clay need not be applied with greatcare since its function is merely to hold the `belting tightly inposition.

At the mid-point 9 of the belting an instrument .such as a lead pencilis now inserted between the shown in Figs. 3 and 4.

A similar funnel-shaped opening Il will now .be formed at I2 where theends of the belting are brought together. f y

I now melt an alloy of bismuth, lead, tin and cadmium lweighingapproximately 4.35 pound per cubic inch, which alloy begins to melt atF. and is completely molten at 190 F. Such alloy should not be heatedover 250 F. This molten alloy is now pouredinto the funnel-shapedopening or gate ,IIJ in a steady stream. After allowing a few minutesfor cooling, the belt 'I may be stripped from the assembly. carryingmost of the clay with it and the alloy Will be found to have rcompletelyfilled groove 3 and to have formed a llet corresponding to the radius ofthe belting. A metal rod is warmed and the end applied to the junctureof the gate and the llet to soften and remove such gate. It isundesirable to heat the metal fillet to a temperature Where it willactually melt since the surface tension of the molten metal acts toround on the otherwise sharp juncture of the llet edge with the pattern.

The same process may be employed in the case of 'a metal pattern butsuch pattern should nrst be heated yuntil it is Warm to the touch, onthe order .of 11,50 F., for example. This may be done quite easily bysubmerging the pattern in hot water and then drying the same.

The above-described alloy, which is commercially available andy soldunder the trade-name of Cerrosafe, expands slightly about one day aftercasting so that the fillet is `firmly and permanently gripped in theundercut cavity t. It will not loosen in use and it is unaffected byliquid parting, kerosene, water, vibration and rough handling. In theevent of damage the fillet can usually be quickly and easily repaired inthe Afoundry with the end of a warm metal rod.

As above indicated, such novel metal llet I5 has been found to beparticularly advantageous when employed in conjunction with a thin metalcoating I3 subsequently applied to the surface of the wooden pattern andpattern plate.Y The usual mahogany pattern after being thoroughlycleaned will have a glue or cement I4 applied thereto which should bespread quite thinly and permitted to become slightly tacky. A preferredadhesive for this purpose is a plastic glue having a high rubber latexcontent. Other types of adhesive such as shellac have been rfound to begenerally unsatisfactory. The same metal alloy used for the fillets isnow sprayed' on the pattern and pattern plate, using ar low temperaturealloy spray gun which is preferably of a type wherein the compressed airis preheated to hold'the particles of atomized metal at the propertemperature. The thin metal coating I3 thus applied cools immediatelyand adheres strongly to the pattern and pattern plate including themetal llets l5 previously provided thereon (Fig.

Such metal surfaced wooden patterns not only last much longer in use butalso give a superior surface to the molds formed thereby. The usualliquid parting fluids which are'regularly employed with metal patternsmay likewise be employed with the same and the metal surface becomessmoother the more the pattern is used. If after a long period of use themetal surface should begin to wear through in spots, a new coating maybe applied. The plastic adhesive which was applied prior to spraying onthe metal, however, becomes quite hard when set and itself provides ahard smooth surface in any minor areas where the metal may thuseventually be worn away. Such metal surfaced wooden patterns are, ofcourse, much less expensive than the all-metal patterns. Importantfactors in the production of a satisfactory metal surfaced woodenpattern include the employment of my new metal fillet, the use of aplastic adhesive rather than shellac or the like, and the use of a lowtemperature alloy spray rather than the high temperature metal sprayssometimes employed for other purposes. .v

It will, of course, be understood that the principles of my inventionare equally applicable to the production of core boxes, for example, andthe term pattern as used herein and in the claims is intended to includeall such similar molding means. While the grooves formed to receive themetal llet will desirably be underout as shown, this is not alwaysabsolutely essential nor is it always essential that the edge of thepattern piece overlie one edge cf such groove. A considerably strongerlock for the fillet is, however, obtained by following such latterpractice, and its use is much preferred.

The pattern (including pattern plate) may comprise a plurality ofseparate parts joined together and thereby forming reentrant angles inwhich I cast my novel fillet. Since such fillet is thus formed in situ,a very perfect fit is obtained and the mechanical interlock ispermanently tight. The pattern parts may be of wood or metal, orcombinations of the same, and changes may be made in my new patternswith a minimum of trouble and expense. The low temperature metal alloyis easy to handle and does no damage to the wooden parts to which thefillet is applied.

As above indicated, a preferred adhesive for the sprayed-on metalcoating is a rubber latexsynthetic resin glue, and I have found a gluemarketed under the trade-name Liqui-Plastic by Wellman Products Company,Cleveland, Ohio, to be excellent for the purpose. Under somecircumstances the use of an adhesive may notl be absolutely essentialalthough it will ordinarily be highly desirable.

Other modes of lapplying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I therefore particularly point out and distinctly claim as my invention:

1. In the manufacture of patterns for the production of sand molds andthe like, the steps of routing out a groove in the surface of a fiatwooden pattern plate following the general peripheral contour of apattern to be mounted thereon, such groove having undercut edges,mounting such pattern upon such plate with the edge of such patternoverlying the inner edge of such groove, thereby forming an insidecorner angle between such pattern and plate, placing a flexibleelongated member of circular cross-section in the angle between suchpattern and plate and in contact with the same, such member having aradius equal to the radius of a desired fillet, securing such member inplace with oil-base modelling clay, forming a pouring sprue of such clayfor admission of molten metal behind such member to such groove, formingan air vent between such member and pattern diametrically opposite suchsprue, pouring a sumcient quantity of an alloy of bismuth, lead, tin,and cadmium fully molten at F. in such sprue to ll such groove and forma metal llet, removing such clay and flexible member after hardening ofsuch fillet, coating such pattern and pattern plate with a thin layer ofa plastic adhesive containing rubber latex, and spraying a thin coatingof the above-identied alloy on suchpattern and pattern plate after suchadhesive has become tacky.

2. In the manufacture of patterns for the production of sand molds andthe like, the steps of forming a groove having undercut edges in the`surface of a flat wooden pattern part following the contour of asmaller pattern part, mounting such smaller pattern part upon such firstpart with its edge overlying an edge of such groove 'but leaving aportion of the width of such groove exposed, removably securing anelongated member of circular cross-section having a radius equal to thedesired fillet radius in the angle between such parts and in contactwith the same, pouring a low melting metal alloy in `such groove andbehind such elongated member to form such llet, removing such memberafter hardening of such fillet, coating such parts with a thin layer ofa plastic adhesive containing rubber latex, and spraying a thin coatingof low melting metal alloy on such parts after such adhesive has becometacky.

3. In combination with a wooden pattern plate and wooden pattern forfoundry molding mounted thereon to form an inside corner angletherebetween, a metal fillet of low melting alloy and desired radiuscast in the angle between plate and pattern, said fillet having anintegral portion filling an undercut groove in the surface of such platefollowing the contour of such pattern with with such pattern overlyingan edge of such groove, a thin hard plastic coating on the exposedsurface of such plate, fillet and pattern, and a thin sprayed coating ofa low melting alloy of bismuth, lead, tin, and cadmium on said rstcoating.

4. A metal surfaced wooden pattern comprising a pattern part having agroove in its surface corresponding generally to the contour outline ofa second pattern part, such groove having undercut edges, a secondpattern part mounted on said ufirst part with its edge overlying an edgeofs'uchfg'roove, therehyiorrning Yan inside corner angle between suchparte a metaillet @111.119 such groove andvforminga desired'radius inthe angle between' Vsaid. parts, 'anfadhesive 4coatingon the exposedsurface of'said parts' aridfnilet, and a thin'metalcoatng'adheredto saidr'st Icoatlne.

5. A Vmetal surfaced V Wooden'pattern comprisin'fga pattern part 'having'agroove in its surface corresponding Fgenerally to -the contour outline4 of a v second pattern part, such"'groove having undercut edges, 'asecQnd pattern part'mounted. `0,11 saidrst part jvvithits edge'adjac'entsuch groove, thereby forming an inside corner Yangle between such parts,a metal fillet filling such groove and forming a desired 'radius intheangle between said parts, means independent of said lletjoining saidVpattern parts together, anda thinmet'al coating adhered to the exposedsurfaces of said Pattern partsand llet. y

`v6. A nietal surfacedwooden pattern 'comprising 'apattern part having a'groove in jits snrface corresponding 'generallywto the contouroutline'of a second pattern par' t, aJ second pattern part mountedon'sai'd r'st part with its edgeloverlyingan edge of such groove,`ametal viijllet lling suchgroove and forming a desired radius in theanglejbetween said parts, means independent of said fillet joining saidpattern parts together,

andja thin metalcoating adhered to the exposed surfaces of'said patternparts and fillet.

7. In combination, a pattern part k having a groove in its surfacecorresponding generally to the contour outline of a second pattern part.

such groove lhaving.undercut Edges, a second patternw part mounted onsaid nrst part with its edge overlying an edge of such `r1C, QY\2,thereby forming an inside corner vangle between such parts, a metalfillet lling 'such groove and forming a desired radius in the .anglebetween said parts, said fillet `being thereby mechanically locked inplace, and means independent of said llet joining the patternpartstogether.

8. In combination, a pattern part having a groove in its surfacecorresponding generally to the contour 'outline of a second patternpart, such groove having undercut edges, 'a second pattern part mountedon said rst part with its edge adjacent auch, elQve. thereby forming..an maiden her angle between such Darts; a 'mtal llet' .ne suchgfrooveand, ,forming a Ydesired radius 'in the angle betwen'said parts,said'llet being thereby.mechancallvflocked inplae, and means'independentof said fillet' joining the pattern ,partstQeether-- '9. .Anattern foruse'rifoundrv moldingand the like 'having 'a groove in one patternsurface correspondingjgenerally 'to the contour outline of a'second'p'attern surface, "such groovehavingundercut edges, saidsecqndjpattern surface overlying an ed'gebfisucngraove thereby'forming'an inside corner 'angle between suchsurfaoes, and a rnet'alfillet filling such groove and'formin'g'a desired'radius in the anglebetween said surfaces, saidv fillet being thereby mechanically locked inplace.

KARL T. RINnERLiE.

A :REFERNCES CITED The refollowingdfreferences are of record inthe le ofthis patent: e

UNITED STATES PATENTS 972,473 isbr'idger et al. Oct. v11, 1910 1,050,201Bellf, Jan. 14, 1913 1,303,430 Washburn e't al. May .13, 1919 1,438,949Dean 1 Dee. 19, 1922 1,857,526 Burnifsh May 10, 1932 2,097,850 WallaceNov. f2, 1937 2,280,864 s tosse1 Apr. 2s, -1942 2,351,919 Bright June20, 1944 2,394,394 Mi11er 1 Feb. i5, V19216 2,479,598 Barber et al. Ag.23, 1949 FOREIGN PATENTS `143,738 :Great Britain June 3, 192D

